Control apparatus for radioreceivers



Oct 24 1933- c. s. DEMAREs'r CONTROL APPARATUS FOR RADIORECEIVERS tub etube Gas ff//en Gasf/V/ed Filed Sept. 22, 1932 605 f//enf V ftube ,SRtube Gas f77/ea' 52 tube Succeedz'mg Zhbs INVENTOR C'. SJI/z/wuces BY$5, 3,151?, etc.

ATTORNEY patented ct. 24, 1933 intesi CONTROL APPARATUS FORRADKORECEIVERS Charles DemarestpRidgewood, N. J., assignor to 'AmericanTelephone and Ilfelegraph Company, a corporation of New York Applicationseptember 2z, 1932 serial No. 634,410`

6 Claims. (Cl. lZ50-20) f This inventionl relates to arrangements forautomatically controlling and vadjusting the operation of a translatingdevice.v Devices with which the arrangements of the invention mightreadily befused are, for example, radio receiving sets, automatic powerYplants, andconstant speed control of motors.

When the arrangements of the invention Vare utilized, for example, forthe automatic control the predetermined signal level is obtained. At`

this point the combination of gas-lled tubes will operate the powersupply for the radio receiver set. The circuit is then held operated atythis level until a different station selection is made or untilswitching means are operated. f Other features, objects and advantagesAwill appear more fully from the detailed description thereofhereinafter given.

The invention may be more fully understood from the followingdescription together with the accompanying drawing in which is shown acircuit diagram embodying a preferred form of the invention.

In'the drawing is shown in diagrammatic form one embodiment of theinvention 'Las applied to automatic tuning of a radio receiver set. Atuned circuit is provided for each station which it is desired toreceive, and so adjusted that, the capacity must be increased to tunethe circuit to resonance with the station frequency. A series of` tubes,A1, B1, A2, B2, etc., control the connection of small capacities inparallel withthe tuning capacities, successive increments of capacitybeing added upon the operation of successive switching tubes S1, S2,etc., until the signal level is suiiicient to operate the nal tube, SR,controlling the power supply for the receiver tube circuits. Theswitching tubes S1, S2, etc., are thereupon disabled so that noadditional capacities are added. When a to the antenna circuit by theselective means shown here' diagrammatically as switch 1. The circuit isalso selectively connected to the radio frequency receiver set throughswitches 2 at the saine time. By means of these switches theV radioreceiver and the antenna may be connected to other tuned circuits asshown in the drawing. Capacities CA and CB are so adjusted for theparticular station desired that lthe circuit is tuned toa somewhathigher frequency than that of the station, and capacity must be added toeach in order to approach resonance with the' station frequency. 1n thisdetuned condition the voltage across coil L2 will, in general, not besufficient -to givev satisfactory output from the receiver andv will notcause operation of tube Sv which has its input circuit adjusted to causeionization in the tube'only at the desiredsignal level. If tube'Sv doesnot operate, the radio receiver power supply remains unoperated by tubeSR. Tube S1, however, has its input circuit adjusted to operate on avery low voltage across coil L2 and this vo-ltage is applied throughpotentiometeri to the rectifier circuit consisting of rectier 4,resistances 5 and 6, and condenser 7. Through the action of therectifier, condenser '7 is charged through resistance 5, the voltageacross this condenser being applied between the grid and cathode of tubeS1 in series with and opposing battery 8. When the resultant gridpotential reaches the ionizing value, an arc is established between theanode and cathode of tube S1 and voltage is applied from source 9through transformers 10 and 11 to the input rectier circuits of tubesA1' and B1. Arcs are then established in these tubes, thus connectingcondensers a1 and a1', and b1 and b1 in parallel, respectively, withcondensers CA and Cs. The anode potentials for tubes A1 and B1 are pro-Vvidedrespectively by batteries 12 and 13. When the arc is established intube S1, voltage is also applied through transformer lli tothe inputrectif-ier circuit of .tube S2 consisting of rectiier 15,7 resistances16, 1'7 and 19, and condenser 18. The charge built up in condenser 18causes direct current tofiow through resistances 17 and 19. The voltagedrop across resistance 19 is applied be'- tween the grid and cathode oftube S2 in series with and opposing the voltage of battery 20. Theresultant grid potential, however, is not made sufliciently positivebythis drop to cause tube S2 to ionize. When the additional capacities areadded to condensers CA and CB through the operation of tubes A1 and B1,the circuit is tuned more closely to resonance with the incom-v lOO Ynection with rectifier and tube S2'.

ing signal and the voltage across coil L2 is increased to such a valuethat tube S2 is ionized by the additional voltage built up acrosscondenser 23 through the action of rectifier 21. Upon the operation oftube S2, voltage is applied from source 24 through transformers 25 and26 to the input rectier circuits of tubes A2 and B2 in the same manneras described for tubes S1, A1 and B1. Voltage is also applied throughtransformer 27 over leads 53 to the rectifier circuit of the tubesucceeding S2, as described in con- Upon the operation of tubes A2 andB2, condensers d2 and b2, a2 and bz are also connected in parallel withcondensers CA and C13, tuning the circuit still more closely toresonance with the incoming signal and increasing the voltage dropacross coil L2 suciently to cause the operation of the tube succeedingS2. The number of tubes similar to S2 may be as many as are necessary togive the desired range of tuning.

When the voltage across coil L2 has been increased by the operation oftubes S1, S2, etc., and reaches a valuewhich is satisfactory for theoperation of the receiver, tube Sv is operated by the voltage built upacross condenser 28 through the action of rectifier 29. When this tubeoperates, voltage is applied from source 30 through transformers 31 and32 to the rectier circuit consisting of rectifier 33, resistances 34,and condenser 35, causing the operation of tube SR. Anode potential fortube SR is provided by battery 38 through resistance 39 and coil 40.Tube SR thus is not self-quenching and remains operated until the offkey K is closed. Voltagefrom source 30 is also applied throughtransformers 37 and 4l to the rectiiier circuit 42 and relay 43, whichcloses the power supply circuit for the radio receiver. When tube Sv isoperated, voltage is also applied through transformer 44 to the recftier circuit `associated with tube S1, consisting of rectifier 45,resistances 46, 47 and 6 and condenser 48. 'This rectifieris soconnected that thevoltage drop produced across resistance 6 is of thesame polarity as battery 8 and places a highvv negative potentialbetween grid and cathode of tube S1, which is thus quenched and remainsso as long as tube Sv is operated. Since the anode potentials of tubesA1 and B1 are provided by batteries, these tubes remain operated eventhrough the input from tube S1 is removed. The grid potential providedby the voltage drop across resistance 19 in the input rectifier circuitof tube S2 is also removed when tube S1 is quenched and this causestubevSz to be quenched since this tube is adjusted to require a largegrid potential, most of which is provided by the voltage drop acrossresistance 19. The voltage built up across condenser 23 is not alonesufficient to ionize tube S2, even with the voltage level across coil L2neces- 'sary to cause operation of tube Sv. The quenching of tube S2causes the quenching of the succeeding tubes in a similar manner. TubesAz and B2 and succeeding tuning tubes remain ionized for the same reasonas tubes A1 and B1, plate potential being provided by batteries in eachcase. l

When it is desired to turn off the receiver, or to tune to anotherstation, the selective means is operated which transfers switches 1 and2 to another similarly tuned circuit and removes the'signal voltageacross coil L2 of the circuit considered above. At the same time key Kis operated either separately or as part of the selec- `tive operationand voltage from source 48 is applied simultaneously to the rectifiervcircuits associated with the anode circuits of tubes Sp., A1, B1, Az,B2, etc. Rectifier 49 in the anode circuit of tube SR charges condenser52 through resistance 50 and directcurrent flows through resistances 51and 39, producing avoltage drop across resistance 39 which opposes thevoltage of battery 38. When the resultant anode potential becomes lessthan that required to sustain ionization, depending upon the gasemployed in the tube, SR is quenched and relay 43 is released, re-

moving `power supply from the receiver. Quenching'of tubes A1, B1, A2,B2, etc., occurs in a similar manner and the auxiliary tuning condensersc1, b1, a1', b1', etc., are disconnected from' condensers CA' and CB,restoring the tuned circuit to the normal condition.

If the-signal voltage across coil L2, at the time the circuitisconnected between the antenna and radio frequency tube V, is strongenough to cause operation of tube Sv immediately, this tube operates andprevents the operation of tube S1 by. virtue of the high negativepotential produced across resistance 6. Since S1 is not operated, S2 andsucceeding tubes will not be operated, as explained above, and noauxiliary condensers will be connected across CA and CB. Tube SR will beoperated and applies power to the receiver at once by operationof relay43.

While thisY invention has been `described in connection with thecircuitarrangements shown, it is understood that other circuit modificationsmay be employed without detracting from the scope of the appendedclaims. Tubes of various types, such as those including-additionalelectrodes, called collectors, not physically connected to the operatingelectrodes, may be of advantage in separating the tuning circuits fromthe operating circuits.

What is claimed is: Y k

1. Radio receiving apparatus comprising an incoming circuit, a receivingset connected to said circuit, a power supply for said receiving set,elements of capacity and inductance includedV in said incoming circuitand so adjusted that said circuit will be tuned slightly bel-owVresonance for a known incoming radio frequency, a series of gas-filleddischarge tubes connected across said incoming circuit and adjusted toide-progressively operated yby variations in the voltage drop acrosssaid inductance element of said known incoming radio frequency, meanscontrolled by said gaslled discharge tubes for connecting additionalelementsof capacity in parallelL with said iirst mentioned elements ofcapacity,- and rneansgop--,

erated by the voltage drop across said inductance set of gas-lleddischarge tubes.

2. A translating device, a receiving circuit connected thereto includingreactance elements so adjusted that saidcircuit will normally be tunedbelow resonance'for an arbitraryfrequency, a

series of gas-filled discharge tubes connected across said receivingcircuit and adjusted to be progressively operated by received currentsVof said arbitrary frequency as said circuit is tuned closer to resonancefor said arbitrary frequency7 means controlled by said'gas-lled tubesfor con-- operativeV when said circuit is tuned by said last 3159?mentioned means to resonance for said arbitrary frequency for operatingsaid translating device.

3. A receiving circuit including reactance elements so adjusted thatsaid circuit will normally be tuned below resonance for an arbitraryfrequency, a second receiving circuit including reactance elements soadjusted that said circuit will normally be tuned below resonance foranother arbitrary frequency, a translating device, switching means foroperatively connecting said translating device to either of saidreceiving circuits, a series of gas-filled discharge tubes connectedacross all of said receiving circuits and adjusted to be progressivelyoperated as either of said circuits when receiving its respectivefrequency and connected to said device is tuned closer to resonance forits respective frequency, means controlled by said gas-filled dischargetubes for connecting additional reactance elements in parallel withcertain of said reactance elements to change the tuning of saidcircuits, and means operative when either of the circuits operativelyconnected to said device is tuned to.

resonance for its respective arbitrary frequency for operating saidtranslating device.

4. A radio receiving device, a receiving circuit including reactanceelements so adjusted that normally said circuit will be tuned belowresonance for an arbitrary incoming radio frequency, switching means foroperatively connecting said circuit to said receiving device, agas-filled discharge tube connected to said receiving circuit andadjusted to operate on a signal level existing when said circuit istuned to resonance for said arbitrary frequency, a second gas-lleddischarge tube connected to said receiving circuit and adjusted tooperate on a substantially lower signal level than said first tube,means controlled by said second tube for connecting additional reactanceelements in parallel with certain of said first mentioned reactanceelements to increase the signal level in said receiving circuit, a thirdgas-filled discharge tube connected to said receiving circuit andadjusted to operate on a higher signal level than said second tube butbelow the level on which said rst tube operates, means controlled bysaid third tube for connecting additional reactance elements in parallelwith certain of said first mentioned reactance elements to furtherincrease vthe signal level in said receiving circuit, means controlledby said second tube when operated for reducing the level at which saidthird tube will operate by an amount sufficient to cause said thirdtubeto operatey when the signal level in said receiving circuit is raised bythe operation of said second tube, and means controlled by the operationof said first tube for operating said radio receiving device.

5. A radio receiving device, a receiving circuit including reactanceelements so adjusted that normally said circuit will be tuned belowresonancefor an arbitrary incoming radio frequency,

switching means for operatively connecting said circuit to saidreceiving device, a gas-filled discharge tube connected to saidreceiving circuit and adjusted to operate on a signallevel existing whensaid circuit is tuned to resonance for said arbitrary frequency, asecond gas-iilled discharge tube connected to said receiving circuit andadjusted to operate on a substantially lower signal level than saidfirst tube, a set of gas-filled discharge tubes operated by theoperation of said second tube for connecting additional reactanceelements in parallel with certain of said first mentioned reactanceelements to increase the signal level in said receiving circuit, a thirdgas-filled discharge tube connected to said receiving circuitandadjusted to operate on a higher level than said second tube but belowthe level on which said first tube operates, a set of gas-filleddischarge tubes operated by the operation of said third tube forconnecting additional reactance elements in parallel with certain ofsaid first mentioned reactance elements to further increase the signallevel in said receiving circuit, means controlled by said second tubewhen operated for reducing the level at which said third tube willoperate by an amount suicient to cause said third tube to operate whenthe signal level in said receiving circuit is raised by theV operationof said second tube, a fourth gas-iilled tube operated by said iirsttube and switching means for operating said radio receiving devicecontrolled by the operation of said fourth tube.

6. A radio receiving device, a receiving circuit including reactanceelements so adjusted that normally said circuit will be tuned belowresonance for an arbitrary incoming radio frequency, switching means foroperatively connecting said circuit to said receiving device, agas-filled discharge tube connected to said receiving circuit andadjusted to operate on a signal level existing when said circuit istuned to resonance for said arbitrary frequency, a second gas-filleddischarge tube connected to said receiving circuit and adjusted tooperate on a substantially lower signal level than said first tube, aset of gas-filled discharge tubes operated by the operation of saidsecond tube for connecting additional reactance elements in' parallelwith certain of said first mentioned reactance elements to increase thesignal level in said receiving circuit, a third gasiilled discharge tubeconnected to said receiving circuit and adjusted to operate on a higherlevel than said second tube but below the level on which said first tubeoperates, a set of gas-filled discharge tubes operated by the operationof said third tube for connecting additional reactance elements inparallel with certain of said first mentioned reactance elements tofurther increase the signal level in said receiving circuit, meanscontrolled by said second tube when operated for reducing the level atwhich said third tube will operate by an amount suiiicient to cause saidthird tube to operate when the signal level in said receiving circuit israised by the operation of said second tube, a fourth gas-filled tubeoperated by said first tube, switching means for operating said radioreceiving device controlled by the operation of said fourth tube, meanscontrolled by the operation of said first tube for extinguishing saidsecond and third tubes, switching means and circuits controlled therebyfor extinguishing said fourth tube and the sets of tubes operated bysaid second and third tubes, and means for adjusting the circuits ofsaid first tube so that it will become, extinguished when the signallevel in said receiving circuit falls below the level existing when saidcircuit is tuned for resonance to said arbitrary incoming frequency.

CHARLES s. DEMAREsT.

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